This invention relates to sealed electrically operated compressors of a scroll type, and more particularly, to a suction pipe connected to a compressor section of the scroll type compressor.
A sealed electrically operated scroll type compressor comprises a compressor section and a motor section contained in a sealed container. Fluid passages penetrate a wall of the sealed container and are connected through ducts to external equipment, such as an evaporator or a condenser, in the case of a refrigerating apparatus. The compressor section of the scroll type compressor comprises a portion having a fixed or stationary scroll member and an orbiting scroll member, with each scroll member including a spiral wrap of an involute curve or the like located in upright position on a respective end plate. A suction port for a fluid is located in a position close to an outer portion of spaces defined by the two scroll members meshing with each other, and an exhaust port opens in a position close to the center of the stationary scroll member.
An Oldham's ring is mounted between the orbiting scroll member and a frame or between the orbiting scroll member and the stationary scroll member to avoid rotation of the orbiting scroll member on its own axis. The orbiting scroll member is in engagement with a crankshaft through bearings with the crankshaft causing the orbiting scroll member to move in orbiting movement without rotating on its own axis, so that the fluid in sealed spaces defined between the two scroll members is compressed and the compressed fluid is discharged through the exhaust port. One example of the sealed electrically operated compressor of the scroll type of the aforesaid construction is disclosed in, for example Japanese Utility Model Application Laid-Open No. 76485/80.
In the sealed electrically operated scroll type compressor disclosed in the above-noted Japanese Publication, a suction pipe and an exhaust pipe extend through the wall of the sealed container and are connected to a suction port and a discharge port opening in the end plate of the stationary scroll member respectively. A refrigerant in a gaseous state of low pressure drawn by suction through the suction pipe is compressed in the sealed spaces and the compressed refrigerant of high pressure is discharged through the exhaust pipe to outside. Thus, in this type of compressor, the internal pressure of the container is kept at a level lower than the high pressure of the compressed fluid, and the temperature is lower than a compressor of the type in which discharged fluid is directly injected into the sealed container. In this type of compressor, the suction pipe may be directly joined as by welding to the wall of the sealed container and to the end plate of the stationary scroll member, because the internal pressure of the sealed container is low and there is no risk that the sealed container, particularly its upper cap section, might suffer deformation due to stress. In another type of compressor disclosed in, for example, Japanese Patent Application Laid-Open No. 46081/80the internal presssure of the sealed container becomes high, the differences in pressure might produce stress high enough to cause deformation to occur within the limit of elasticity and this phenomenon would not be negligible. The production of stress might subject the suction pipe to forced deformation, thereby causing crak formation to take place. If the crack formation occurs in the suction pipe, the fluid of high pressure in the sealed container would flow into the suction pipe and then into the compression chamber, so that the fluid can not be drawn by suction into the sealed container from the low pressure side of the refrigeration cycle and the refrigeration cycle can not be established. To avoid this trouble, in, for example, Japanese Patent Laid Open Application No. 148994/80, a proposal has been made to mount a suction pipe in a manner to keep it from coming into contact with an upper cap which is liable to suffer deformation.
In this proposal, the suction pipe is connected to an opening formed in a portion of an inner wall surface of the sealed container at which the stationary scroll member is fitted and secured in place. Thus, the suction pipe is not directly secured to the upper cap, so that the suction pipe is prevented from being subjected to forced deformation even if the upper cap is deformed due to stress, and the crack formation is prevented from occurring in the suction pipe.
When the suction pipe is connected to the sealed container in such a manner that it projects from the sealed container in a direction perpendicular to the axis of the sealed container, it is necessary to increase the thickness of the stationary scroll member in a portion thereof in which the suction pipe is connected thereto. Thus, this proposal would suffer the disadvantage that the overall size of the sealed container would increase.
This invention has as its object the provision of a sealed type electrically operated compressor including a sealed container of a compact size which prevents crack formation in the suction pipe which might otherwise be caused to occur by stress due to high pressure.
The aforesaid object is accomplished according to the invention by providing a suction pipe defining a suction passage which penetrates at one end portion thereof the end plate of the stationary scroll member to open in a fluid suction space defined by the stationary and the orbiting scroll members meshing with each other, and which extends at the other end portion thereof axially through a wall of the cylindrical sealed container to communicate with external equipment on the low pressure side, and a gas sealing member attached to the suction pipe, the suction pipe being securely connected at one of two opposite end portions to the wall of the cylindrical sealed container, and being non-securely connected at the other end portion to the end plate of the stationary scroll member so that the sealing member is attached to the end portion of the suction pipe that is non-securely connected.